T-Mobile US has announced the Un-carrier has overtaken rivals ATT, Verizon and Sprint to become the No.1 U.S. wireless provider in the increasingly important prepaid mobile marketplace. Here's the info from T-Mobile's announcement:

According to the most recent reported figures, T-Mobile US now boasts 15.64 million prepaid customers compared to Sprint's 15.19 million customers in the prepaid market. ATT most recently reported 11.34 million prepaid customers. Verizon Wireless reports 6.04 million prepaid customers.

Providers have been placing increasing emphasis on this important area of the mobile marketplace. Still, no wireless company has seen nearly the success the Un-carrier has in this critical market.

The T-Mobile's MetroPCS brand in particular has seen unprecedented gains since merging with T-Mobile on May 1st of last year. MetroPCS effectively tripled its market reach to 45 major metro areas and nearly 10,000 stores, while migrating its customers onto America's fastest nationwide 4G LTE network. This aggressive expansion of markets and coverage has led MetroPCS to grow to over 10 million customers--and the numbers continue to climb.

In fact, with over 1.2 million new customers since this time last year, MetroPCS has been adding customers at a rate of one customer every 27 seconds.